1. Field of the Invention
The present invention relates to an engine control apparatus for preventing an internal combustion engine such as an outboard engine, from excessive revolution.
2. Discussion of Background
In a conventional outboard engine provided with an analogue control circuit, when an abnormal state of the engine, e.g. overheating of the engine is detected, misfiring is caused at all cylinders to thereby reduce the revolution speed of the engine, and when the revolution speed becomes a predetermined value or lower, all the cylinders are again ignited. Accordingly, the conventional outboard engine has a disadvantage of a large change in the number of revolutions of the engine.
In the worst case, a ship with the outboard engine on the sea cannot sometimes return to a harbor in a case that the engine completely stops when the abnormality is detected.
Thus, in the conventional engine control apparatus, there was a disadvantage of a large change in the revolution speed since the misfiring is caused at all cylinders when the abnormality is detected.